Being able to maneuver multiple cursors is really awesome. The following is a list of things that I think would be really, really great :)

Make is possible to focus cursors when multiple exists (i.e. leave some of the multiple cursors idle). This could be activated by clicking the cursor you want to focus with your mouse while holding down some keys but preferable some hotkeys should exist as well. Once a single cursor has the focus it would also be great with hotkeys for focusing the previous/next cursor

Make it possible to spawn a new cursor at the some position as the current one(s) leaving the old one(s) idle. This could work a quick bookmark functionality together with the previous suggestions but I could find a lot of other fun uses like pre/post-fixing a word at the same time: spawn cursor, ctrl + w, ctrl + f, extend cursor selection to previous cursor, start typing.